JSON Prompt Builder

Visually build OpenAI and Anthropic API message arrays. Copy JSON or cURL. Supports variables.

Variables

JSON Output

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "system",
      "content": "You are a helpful assistant."
    },
    {
      "role": "user",
      "content": "Hello, {{topic}}"
    }
  ]
}

cURL Command

curl https://api.openai.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -d '{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "system",
      "content": "You are a helpful assistant."
    },
    {
      "role": "user",
      "content": "Hello, {{topic}}"
    }
  ]
}'

Help Us Improve

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Visually build and customize OpenAI and Anthropic API message arrays without writing code. Export ready-to-use JSON or cURL commands instantly. Perfect for testing prompts, building integrations, or learning API structures.

How it works

1Select your AI provider (OpenAI or Anthropic)
2Add messages visually using the builder interface
3Configure variables and parameters as needed
4Copy JSON or cURL command to use immediately

Who uses this tool

✓Developers testing API calls before coding integrations
✓Prompt engineers iterating and refining message structures
✓Teams building chatbot systems and AI workflows
✓Students learning OpenAI and Anthropic API fundamentals
✓Product managers prototyping AI features quickly

Frequently Asked Questions

How do I use JSON Prompt Builder?

Build structured JSON prompts visually by adding fields, setting values, and previewing the formatted prompt in real time.

Is JSON Prompt Builder free?

Yes, JSON Prompt Builder on ToolPix is 100% free with no signup or installation required.

Is my data safe?

All processing happens in your browser, your data never leaves your device.

Who is JSON Prompt Builder designed for?

Developers, content creators, and anyone working with AI tools who wants to get better results faster.

Can I save my work?

Results can be copied to clipboard with one click. Browser local storage keeps your recent sessions.

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